Shp2 protein tyrosine phosphatase (FTP) mediates growth factor receptor signaling and regulates cellular activities critical to tumor growth and metastasis. Shp2 is employed by the carcinogenic Helicobactor pylori CagA protein to cause gastric cancer. Shp2 activating mutations have been linked to the developmental disorder Noonan syndrome and are associated with leukemias and solid tumors. However, the detailed mechanisms by which Shp2 mediates cell signaling, carcinogenesis and metastasis remain incompletely understood. No small molecule Shp2 inhibitor is currently available for targeted therapy and chemical genetic studies. Based on molecular biology evidence, we postulate that Shp2 is an important enzyme for development of targeted cancer therapy. The overall goal of this project is to identify small organic molecules of Shp2-selective FTP inhibitors as potential agents for molecularly.targeted cancer therapy and as tools for chemical genetic interrogation of Shp2 signaling mechanisms. Three specific aims will be pursued in the current study. We have identified two lead compounds of Shp2 inhibitors. In Aim I, we will synthesize focused chemical libraries based on these lead compounds, screen a larger diverse chemical library, and characterize Shp2 inhibitors in vitro to obtain Shp2 inhibitors with better potency, selectivity, and drug-like properties. In Aim II, we will evaluate Shp2 inhibitors for their ability to inhibit epidermal growth factor (EGF)-stimulated Shp2 activation and activity of an activated Shp2 mutant in cell cultures, whether they have off-target effects, and their stability in cell cultures. Promising Shp2 inhibitors will be further evaluated in Aim III for their activities in inhibition of transformed phenotypes in cell cultures and in tumor xenografts. This interdisciplinary study will identify promising Shp2-selective inhibitors and provide pharmacological evidence for validation of Shp2 FTP as a drug target for clinical development of Shp2- targeted cancer therapy. Lay statement: Shp2 is a protein that plays a critical role in the development of various forms of human cancer and other diseases. We will discover and characterize Shp2 inhibitors. This will lay the foundation for further clinical development of new drugs targeting Shp2 for cancer intervention and provide much- needed chemical probes for understanding the functionality of Shp2 in human diseases.